Positive crankcase ventilation (PCV) systems are provided in engines to reduce the amount of blow-by gasses escaping into the environment. Resultantly, PCV systems enable engine emissions to be reduced. However, positive crankcase ventilation (PCV) vapor contains a large fraction of water. Additionally, other sources of water may be present in the intake system, such as water vapor from an exhaust gas recirculation (EGR) system. The water vapor can condense on the cold air duct walls, intake conduits, and within the intake manifold. Further, the PCV vapor may freeze into ice downstream of the PCV port in the cold air duct. Following a diurnal cycle, the melted ice may drip and/or drain down to depressions in the intake system and re-freeze. Once the engine is restarted, the ice may melt and can move downstream to the cylinders. The condensate flowing into the cylinders degrades combustion and in some cases cause misfires in the cylinder, due to spark plug wetting.
U.S. Pat. No. 6,290,558 discloses a water trap in an exhaust system. The inventors have recognized several drawbacks with the water trap disclosed in U.S. Pat. No. 6,290,558. The structural features of water trap disclosed in U.S. Pat. No. 6,290,558 limits the amount of water that can be collected in the trap. Additionally, the features of the water trap also increase turbulence in the exhaust system.
As such in one approach, an engine intake manifold is provided. The engine intake manifold includes a manifold chamber configured to receive positive crankcase ventilation (PCV) gas from a PCV conduit outlet, the manifold chamber including a condensate-containment tray with a plurality of baffles to form a plurality of separate cavities below the PCV conduit outlet. It has been unexpectedly found that when the aforementioned structural features of the intake manifold, and in one example the condensate-containment tray, are provided in an engine, condensate can be collected and released into the cylinders at a desired rate which can reduce the likelihood of combustion degradation (e.g., misfires).
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. Additionally, the above issues have been recognized by the inventors herein, and are not admitted to be known.